1. Field of the Invention
The present invention relates to a film handling means and more specifically to means for detecting the presence of a film strip in a film receiving location of a photographic printer.
2. Description Relative to the Background Art
Commonly assigned U.S. Pat. No. 4,774,553 discloses a film handling mechanism for a photographic printer which provides for film movement at a gate in all directions in the film plane including rotation. The mechanism includes a guiding means which define a thin elongate rectangular space or slot for receiving a 35 mm film strip containing up to four frames. In use the end of the film strip is inserted by the user and is moved into the slot by belts driven by a motor. After the film strip is received in the slot, a door for enclosing the entrance to the slot is closed to light seal the space.
To control operation of the motor driven belt mechanism and to prevent damage to film strips of abnormal lengths it is desirable to detect both the insertion of the leading end of the film strip by the user and the containment of the entire film strip by the slot. Detection of the leading end is desirable to activate the belt transport mechanism and detection of the complete containment is desirable to warn against or prevent closure of the door if the film strip is not fully contained.